Possibly f**ked up IAC or ISC? Dunno...vid inside

[KaMaSuTrA]

I think either my ISC or IAC has gone bad but i'm not exactly sure. The car has lately been having some erratic starts in the cold morning where the car would surge almost on and off like as if someone was flipping a light switch under my hood (damn....elves!) The rpm bounces and u can hear clicking through the whole time this is happening as if u where turning the key forward normally but imagine it while you are driving and the car is just surging on and off. I have also notice a slight crackling noise around the throttle body that sounds like someone lit a bowl of rice-crispies on fire. This crackling noise only happens on the cold starts but everything else follows suit no matter what the weather is like.

Anyone has an idea wtf is going on? The car is not on in the vid and the ignition is just primed.

http://www.divinityracing.com/Vids/crackling.mpg

 

[dieseltech]

Have you tried to unplug the IAC when it's doing this? If so, does the sound go away? That sounds soo cool. Oh, are your battery connnections good? Are the ground and supply connnections good on the motor? Bad grounds make things go clickyclick like that. Just a few suggestions.

 

[grnchevyz]

hmm...is this clicking sound mechanical (like a relay) or more like a rock in the intake kinda sound? hard to tell on the vid.

If it's a relay, then check your grounds and make sure all connectors around the "noise" are well seated.

also, this sound could be coming from anywhere else in the engine and resonating through the TB/IM.

Let us know which of the 2 sounds and we'll take it from there.

 

[KaMaSuTrA]

Sound more like rocks inside the intake. I disconnected the ISC connector and the car seems to be running smoother. I took it for a spin but it feels like theres a small mis-fire at idle 1000rpm. It doesn't feel like its about to dump on me when i change gears but i just hate the small misfire i'm getting. I'm not planning on running it like this since it worked before with it connected and i might just #### something else up in the process. Anyone else have ideas on whats going on?
Like i said it only clicks when its surging and that when i'm about to leave a parking spot from a cold start.

 

[steve]

I ony hear them chattering that long when the ECU is messed up.
A bad driver or ISC usually only rattles for a second or two then you first turn the ignition on.

Measure the ISC coil resistance per the VFAQ to make sure none of the coils is shorted and then try a different ECU.

Steve

 

[KaMaSuTrA]

I ony hear them chattering that long when the ECU is messed up.
A bad driver or ISC usually only rattles for a second or two then you first turn the ignition on.

Measure the ISC coil resistance per the VFAQ to make sure none of the coils is shorted and then try a different ECU.

Steve

Opened up the ECU and found leaky caps......going to swap it out so we'll see if that helps. Thanks for the replies everyone

 

[steve]

Bring it by and I'll see how bad it is.

Steve

 

[KaMaSuTrA]

Managed to get another ecu and swapped it out. Also found out that my AFC settings were a bit off from where they were originally set...dunno how that happened. Its running a lot better now and it doesn't surge at all. Now it just needs a set of new wires.

As for fixing the old one i'm looking into stand alone management so i might go eprom w/DSMlink i just need my funds to go back to normal. I'll contact u if anything steve thanks.